Twenty college students experience the effects of alcohol on reaction time.They perform very basic timed responses in a driving simulator both before and after consuming several alcoholic beverages.The researcher collects a reaction time result for each of the 20 students before and after intoxication, for a total of 40 measures.What are the degrees of freedom for this study?
A) 19
B) 20
C) 39
D) 40

Question

Quizplus · Accepted Answer

The degrees of freedom for a paired t-test, which is appropriate here since the same subjects are measured twice, is n - 1, where n is the number of pairs. Here, n = 20, so the degrees of freedom is 20 - 1 = 19.

Twenty College Students Experience the Effects of Alcohol on Reaction